Bot payload alignment and sensing

ABSTRACT

An autonomous transport robot for transporting a payload, the autonomous transport robot includes a payload bed having at least one reference datum surface and at least one payload justification device, the at least one payload justification device being configured to position a payload on the payload bed in substantial contact with the at least one reference datum surface to place the payload in a predetermined position on the payload bed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/942,717, having a filing date of Nov. 16, 2015, which is acontinuation of and claims the benefit of U.S. application Ser. No.13/327,040, having a filing date of Dec. 15, 2011 (now U.S. Pat. No.9,187,244 issued Nov. 17, 2015), which is a non-provisional of andclaims the benefit of U.S. Provisional Patent Application No.61/423,220, filed on Dec. 15, 2010, the disclosures of which areincorporated by reference herein in their entireties.

BACKGROUND

1. Field

The embodiments generally relate to storage and retrieval systems and,more particularly, to autonomous transports of the storage and retrievalsystems.

2. Brief Description of Related Developments

Warehouses for storing case units may generally comprise a series ofstorage racks that are accessible by transport devices such as, forexample, fork lifts, carts and elevators that are movable within aislesbetween or along the storage racks or by other lifting and transportingdevices. These transport devices may be automated or manually driven.Generally the items transported to/from and stored on the storage racksare contained in carriers, for example storage containers such as trays,totes or shipping cases, or on pallets.

When transporting the cases to and from the storage racks with automatedtransports it would be advantageous to be able to locate the casesrelative to the automated transport while holding the case securelyduring transport.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and other features of the disclosed embodimentsare explained in the following description, taken in connection with theaccompanying drawings, wherein:

FIG. 1 schematically illustrates an exemplary storage and retrievalsystem in accordance with the embodiments;

FIG. 2 illustrates a schematic plan view of an exemplary storage andretrieval system in accordance with the embodiments;

FIG. 3 illustrates a structural portion of a storage and retrievalsystem in accordance with the embodiments;

FIGS. 4A and 4B illustrate storage shelves in accordance with theembodiments;

FIG. 5 is an illustration of the exemplary autonomous transport vehiclein accordance with the embodiments;

FIG. 6 is a schematic illustration of a portion the exemplary autonomoustransport vehicle of FIG. 5 in accordance with the embodiments;

FIG. 7A is a schematic illustration of a portion the exemplaryautonomous transport vehicle of FIG. 5 in accordance with theembodiments;

FIG. 7B is another schematic illustration of a portion the exemplaryautonomous transport vehicle of FIG. 5 in accordance with theembodiments;

FIG. 7C is an illustration of the exemplary autonomous transport vehiclein accordance with an aspect of the disclosed embodiment;

FIG. 8 is a schematic illustration of a portion the exemplary autonomoustransport vehicle of FIG. 5 in accordance with the embodiments;

FIG. 9 is a schematic illustration of a portion the exemplary autonomoustransport vehicle of FIG. 5 in accordance with the embodiments;

FIG. 10 is an illustration of a portion of the exemplary autonomoustransport vehicle of FIG. 5 in accordance with the embodiments; and

FIG. 11 is a flow diagram in accordance with the embodiments.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT(S)

FIG. 1 schematically illustrates an exemplary storage and retrievalsystem in accordance with the embodiments. Although the disclosedembodiments will be described with reference to the embodiments shown inthe drawings, it should be understood that the disclosed embodiments canbe embodied in many alternate forms. In addition, any suitable size,shape or type of elements or materials could be used.

In accordance with the embodiments the storage and retrieval system 100may be substantially similar to that described in, for example, U.S.patent application Ser. No. 12/757,381, entitled “STORAGE AND RETRIEVALSYSTEM” and filed on Apr. 9, 2010, and U.S. Provisional PatentApplication No. 61/423,340 entitled “Warehousing Scalable StorageStructure” and filed on Dec. 15, 2010 (now U.S. patent application Ser.No. 13/326,674 filed on Dec. 15, 2011), the disclosures of which areincorporated by reference herein in their entireties and may operate ina retail distribution center or warehouse to, for example, fulfillorders received from retail stores for case units (where case units asused herein means items not stored in trays, on totes or on pallets,e.g. uncontained or items stored in trays, totes or on pallets). It isnoted that the case units may include cases of items (e.g. case of soupcans, boxes of cereal, etc.) or individual items that are adapted to betaken off of or placed on a pallet. In accordance with the embodiments,shipping cases or case units (e.g. cartons, barrels, boxes, crates,jugs, totes, pallets or any other suitable device for holding caseunits) may have variable sizes and may be used to hold items in shippingand may be configured so they are capable of being palletized forshipping. It is noted that when, for example, bundles or pallets of caseunits arrive at the storage and retrieval system the content of eachpallet may be uniform (e.g. each pallet holds a predetermined number ofthe same item—one pallet holds soup and another pallet holds cereal) andas pallets leave the storage and retrieval system the pallets maycontain any suitable number and combination of different items (e.g.each pallet may hold different types of items—a pallet holds acombination of soup and cereal). In alternate embodiments the storageand retrieval system described herein may be applied to any environmentin which case units are stored and retrieved.

The storage and retrieval system 100 may be configured for installationin, for example, existing warehouse structures or adapted to newwarehouse structures. In the embodiments, the storage and retrievalsystem may include in-feed and out-feed transfer stations 170, 160,multilevel vertical conveyors 150A, 150B, a storage structure 130, and anumber of autonomous transport vehicles or robots 110 (referred toherein as “bots”). The storage and retrieval system may also includerobot or bot transfer stations (as described in, for example, U.S.patent application Ser. No. 12/757,220, entitled “STORAGE AND RETRIEVALSYSTEM” and filed on Apr. 9, 2010, the disclosure of which isincorporated by reference herein in its entirety) that may provide anindirect interface between the bots 110 and the multilevel verticalconveyor 150A, 150B. The in-feed transfer stations 170 and out-feedtransfer stations 160 may operate together with their respectivemultilevel vertical conveyors 150A, 150B for bi-directionallytransferring case units to and from one or more levels of the storagestructure 130. It is noted that while the multilevel vertical conveyorsare described herein as being dedicated inbound or in-feed conveyors150A and outbound or out-feed conveyors 150B, each of the conveyors150A, 150B may be used for both inbound and outbound transfer of caseunits/items from the storage and retrieval system. The multilevelvertical conveyors may be any suitable lifting devices for transportingcase units between levels of the storage and retrieval system. It isnoted that while multilevel vertical conveyors are described herein inother aspects the conveyors may be any suitable conveyors ortransfer/picking devices having any suitable transport path orientation.Some non-limiting suitable examples of multilevel vertical conveyors canbe found in, for example, U.S. patent application Ser. No. 12/757,354,entitled “LIFT INTERFACE FOR STORAGE AND RETRIEVAL SYSTEMS” and filed onApr. 9, 2010, and U.S. Provisional Patent Application No. 61/423,298entitled “LIFT INTERFACE FOR STORAGE AND RETRIEVAL SYSTEMS” and filed onDec. 15, 2010 (now U.S. Pat. No. 8,998,554 issue on Apr. 7, 2015), thedisclosures of which are incorporated by reference herein in theirentireties and U.S. patent application Ser. No. 12/757,220, entitled“STORAGE AND RETRIEVAL SYSTEM,” (previously incorporated by reference).For example, the multilevel vertical conveyors may have any suitablenumber of support shelves for transporting the case units to apredetermined level of the storage and retrieval system. The supportshelves may have slatted supports configured to allow fingers of thebots 110 or in-feed/out-feed transfer stations 170, 160 to pass betweenthe slats for transferring case units to and from the conveyor. It isnoted that in the embodiments transfer of case units between the botsand the multilevel vertical conveyors may occur in any suitable manner.

As may be realized, the storage and retrieval system 100 may includemultiple in-feed and out-feed multilevel vertical conveyors 150A, 150Bthat are accessible by, for example, bots 110 on each level of thestorage and retrieval system 100 so that one or more case unit(s) can betransferred from a multilevel vertical conveyor 150A, 150B to eachstorage space on a respective level and from each storage space to anyone of the multilevel vertical conveyors 150A, 150B on a respectivelevel. The bots 110 may be configured to transfer the case units betweenthe storage spaces and the multilevel vertical conveyors with one pick(e.g. substantially directly between the storage spaces and themultilevel vertical conveyors). By way of further example, thedesignated bot 110 picks the case unit(s) from a shelf of a multilevelvertical conveyor, transports the case unit(s) to a predeterminedstorage area of the storage structure 130 and places the case unit(s) inthe predetermined storage area (and vice versa).

The bots 110 may be configured to place case units, such as the abovedescribed retail merchandise, into picking stock in the one or morelevels of the storage structure 130 and then selectively retrieveordered items for shipping the ordered items to, for example, a store orother suitable location. In the embodiments, the bots 110 may interfacein any suitable manner with the multilevel vertical conveyors 150A, 150Bsuch as through, for example, extension of a transfer arm or effector ofthe bot (which may have fingers for interfacing with slatted supportshelves of the multi-level vertical conveyors) relative to a frame ofthe bot. Suitable examples of bots are described in U.S. patentapplication Ser. No. 12/757,312, entitled “AUTONOMOUS TRANSPORTS FORSTORAGE AND RETRIEVAL SYSTEMS” and filed on Apr. 9, 2010, U.S.Provisional Patent Application No. 61/423,365 entitled “AUTOMATED BOTWITH TRANSFER ARM” and filed on Dec. 15, 2010 (now U.S. patentapplication Ser. No. 13/326,952 filed on Dec. 15, 2011), U.S.Provisional Patent Application No. 61/423,388 entitled “AUTOMATED BOTTRANSFER ARM DRIVE SYSTEM” and filed on Dec. 15, 2010 (now U.S. patentapplication Ser. No. 13/326,993 filed on Dec. 15, 2011), U.S.Provisional Patent Application No. 61/423,359 entitled “BOT HAVING HIGHSPEED STABILITY” and filed on Dec. 15, 2010 (now U.S. Pat. No. 8,965,619issued on Feb. 24, 2015), and U.S. Provisional Patent Application No.61/423,206 entitled “BOT SENSING POSITION” and filed on Dec. 15, 2010(now U.S. Pat. No. 9,008,884 issued on Apr. 14, 2015), the disclosuresof which are incorporated by reference herein in their entireties.

The storage structure 130 may include multiple levels of storage rackmodules where each level includes an array of storage spaces (arrayed onthe multiple levels and in multiple rows on each level), picking aisles130A formed between the rows of storage spaces, and transfer decks 130B.It is noted that, each level may also include respective bot transferstations for providing an indirect interface between the bots and themultilevel vertical conveyors. In the embodiments, the picking aisles130A and transfer decks 130B may be arranged for allowing the bots 110to traverse respective levels of the storage structure 130 for placingcase units into picking stock and to retrieve the ordered case units. Asmay be realized, the storage and retrieval system may be configured toallow random accessibility to the storage spaces. For example, allstorage spaces in the storage structure 130 may be treated substantiallyequally when determining which storage spaces are to be used whenpicking and placing case units from/to the storage structure 130 suchthat any storage space of sufficient size can be used to store items.The storage structure 130 of the embodiments may also be arranged suchthat there is no vertical or horizontal array partitioning of thestorage structure. For example, each multilevel vertical conveyor 150A,150B is common to all storage spaces (e.g. the array of storage spaces)in the storage structure 130 such that any bot 110 can access eachstorage space and any multilevel vertical conveyor 150A, 150B canreceive case units from any storage space on any level so that themultiple levels in the array of storage spaces substantially act as asingle level (e.g. no vertical partitioning). The multilevel verticalconveyors 150A, 150B can also receive case units from any storage spaceon any level of the storage structure 130 (e.g. no horizontalpartitioning). It is also noted that the storage and retrieval systemmay be configured so that each multilevel vertical conveyor serves apredetermined area of the array of storage spaces.

The storage structure 130 may also include charging stations 130C forreplenishing, for example, a battery pack of the bots 110. In theembodiments, the charging stations 130C may be located at, for example,transfer areas 295 (FIG. 2) of the transfer deck 130B so that the bots110 can substantially simultaneously transfer items, for example, to andfrom a multilevel vertical conveyor 150A, 150B while being charged. Thebots 110 and other suitable features of the storage and retrieval system100 may be controlled by, for example, one or more central systemcontrol computers (e.g. control server) 120 through, for example, anysuitable network 180. The network 180 may be a wired network, a wirelessnetwork or a combination of a wireless and wired network using anysuitable type and/or number of communication protocols. It is notedthat, in the embodiments, the system control server 120 may beconfigured to manage and coordinate the overall operation of the storageand retrieval system 100 and interface with, for example, a warehousemanagement system 125, which in turn manages the warehouse facility as awhole. The control server 120 may be substantially similar to thatdescribed in, for example, U.S. patent application Ser. No. 12/757,337,entitled “CONTROL SYSTEM FOR STORAGE AND RETRIEVAL SYSTEMS” and filed onApr. 9, 2010 (the disclosure of which is incorporated by referenceherein in its entirety).

Referring also to FIG. 2, an exemplary configuration of the storage andretrieval system 100 is shown. Other suitable exemplary configurationsof storage and retrieval systems can be found in, for example, U.S.Provisional Patent Application No. 61/423,340 entitled “WarehousingScalable Storage Structure” and filed on Dec. 15, 2010 (now U.S. patentapplication Ser. No. 13/326,674 filed on Dec. 15, 2011), and U.S. patentapplication Ser. No. 12/757,381, entitled “STORAGE AND RETRIEVAL SYSTEM”and filed on Apr. 9, 2010 (the disclosures of which are incorporated byreference herein in their entireties). It should be understood that thestorage and retrieval system may have any suitable configuration. As canbe seen in FIG. 2, the storage and retrieval system 200 is configured,for exemplary purposes only, as a single-ended picking structure inwhich only one side of the system 200 has a transfer section or deck130B. The single-ended picking structure may be used in, for example, abuilding or other structure having loading docks disposed only on oneside of the building. In the embodiments, the storage and retrievalsystem 200 includes transfer deck(s) 130B and picking aisles 130A thatallow bots 110 to traverse an entirety of a level of the storagestructure 130 on which that bot 110 is located for transporting itemsbetween any suitable storage locations/picking aisles 130A and anysuitable multilevel vertical conveyors 150A, 150B. The multilevelvertical conveyors 150A, 150B provide transport of case units into thestorage and retrieval system 200 through input workstations 210 andprovide output of case units from the storage and retrieval system 200through output workstations 220. In the embodiments, the storage andretrieval system 200 includes a first and second storage section 230A,230B located side by side so that the picking aisles of each section aresubstantially parallel with each other and facing the same direction(e.g. towards transfer deck 130B). It is noted that the storage andretrieval system may have any suitable number of storage sectionsarranged relative to each other in any suitable configuration.

Referring to FIGS. 1, 3, 4A and 4B, each of the storage bays 510, 511 ofthe storage structure 130 may hold the picking stock on storage shelves600 that are separated by aisle spaces 130A. In the embodiments thestorage bays 510, 511 and storage shelves 600 may be substantiallysimilar to those described in, for example, U.S. patent application Ser.No. 12/757,220, entitled “STORAGE AND RETRIEVAL SYSTEM,” and U.S. patentapplication Ser. No. 12/757,381, entitled “STORAGE AND RETRIEVAL SYSTEM”(both of which being previously incorporated by reference). For example,the storage shelves 600 may include one or more support legs 620L1,620L2 extending from, for example, the horizontal supports 610, 611, 613(which are supported by vertical supports 612). The support legs 620L1,620L2 may have any suitable configuration and may be part of, forexample, a substantially U-shaped channel 620 such that the legs areconnected to each other through channel portion 620B. The channelportion 620B may provide an attachment point between the channel 620 andone or more horizontal supports 610, 611, 613. It is noted that, eachsupport leg 620L1, 620L2 may also be configured to individually mount tothe horizontal supports 610, 611, 613. In the embodiments, each supportleg 620L1, 620L2 includes a bent portion 620H1, 620H2 having a suitablesurface area configured to support case units stored on the shelves 600.The bent portions 620H1, 620H2 may be configured to substantiallyprevent deformation of the case units stored on the shelves. It is notedthat the leg portions 620H1, 620H2 may have a suitable thickness or haveany other suitable shape and/or configuration for supporting case unitsstored on the shelves. As can be seen in FIGS. 4A and 4B, the supportlegs 620L1, 620L2 or channels 620 may form a slatted or corrugated shelfstructure where spaces 620S between, for example, the support legs620L1, 620L2 allow for arms or fingers of the bots 110 to reach into theshelving for transferring case units to and from the shelves. It is alsonoted that transfer of items to and from the multilevel verticalconveyors 150A, 150B (whether the transfer is made directly orindirectly by the bot 110) may occur in a substantially similar mannerto that described above with respect to the storage shelves 600. It isnoted that the spacing between the case units on the shelves may be anysuitable spacing. It is also noted that transfer of case units to andfrom the multilevel vertical conveyors 150A, 150B (whether the transferis made directly or indirectly by the bot 110) may occur in asubstantially similar manner to that described above with respect tostorage shelves 600.

Referring to FIG. 5 an exemplary bot 110 is shown. In the embodimentsthe bot 110 includes a longitudinally extended frame 110F that has afirst end 1500 and a second end 1501 where the longitudinal axis 6000extends from the first end 1500 to the second end 1501. At least onedrive section 110D may be coupled to one of the first and/or second ends1500, 1501 in any suitable manner for driving the bot 110 along thetransfer deck(s) 130B and picking aisles 130A (FIG. 1). The drive 110Dmay include drive wheels, tracks or any other suitable drive mechanismfor effecting travel of the bot along the transfer deck(s) 130B andpicking aisles 130A. The other end of the bot 110 may have any suitablesupports, such as caster wheels, fixed wheels, steerable wheels, andsimilar mechanisms for movably supporting the bot 110 as it travelsalong the transfer deck(s) 130B and picking aisles 130A. The bot 110 mayhave any suitable controller 1220 (FIG. 1) for effecting operation ofthe bot 110 (as described herein) and/or communication between the bot110 and the control server 120 (FIG. 1). As may be realized theconfiguration of the bot shown in the drawings is merely exemplary andit should be understood that the bot may have any suitable configurationfor carrying out the detection and positioning of case units relative tothe bot 110 as described herein.

Referring now to FIGS. 5, 6, 7A and 7B the frame 110F of the bot 110forms a payload bed 1510 that is configured to hold case units or anyother suitable payload. The payload bed 1510 may be suitably sized foraccepting (e.g. holding) any case unit 1700 (or pickface 1700P where apickface is one or more cases that is to be picked and carried by thebot 110) that may be transferred into or removed from the storage andretrieval system 100. For example, in the embodiments the payload bed1510 may be larger than an expected pick size (i.e. larger than thepickface 1700P the bot is expected to pick from, for example, thestorage shelf 600 or any other suitable component of the storage andretrieval system such as the multilevel vertical conveyors). In thisexample, the pickface 1700P is shown as including two case units 1700arranged laterally with respect to longitudinal axis 6000 of the bot110. However, the pickface may include any suitable number of case unitsarranged laterally, longitudinally or in a lateral/longitudinal gridpattern.

The payload bed 1510 may include any suitable guide surfaces forallowing the case units to be transferred into the payload bed 1510without obstruction. For example, in the embodiments the frame 110Fforming the payload bed 1510 may include one or more flanges 1510C1,1510C2 on the sides 1510S1, 1510S2 of the payload bed 1510. In thisexample, the flanges 1510C1, 1510C2 may be chamfered or angled surfacesat a top opening 1510TP of the payload bed 1510. The angled surfacessubstantially form a wedge shape so that on contact with an edge of thecase unit during transfer of the pickface into the payload area (e.g.lowering of the case unit into the payload area in the direction ofarrow 1673) the angled surfaces guide the case unit(s) 1700 of thepickface 1700P into the payload area without obstructions (e.g. the caseunit(s) being snagged or otherwise caught on a portion of the bot 110).The unobstructed transfer of the case units to the bot payload areafacilitates loading of the case unit in one pick (e.g. substantiallywithout repositioning the pickface or retrying the loading of thepickface onto the bot 110). While in this example the flanges 1510C1,1510C2 are shown as being substantially straight surfaces it should beunderstood that the flanges may have any suitable shape and/orconfiguration such as for exemplary purposes only, arcuate. Also in thisexample, the flanges 1510C1, 1510C2 are shown as terminatingsubstantially at an edge 1510E of the payload area, but it should beunderstood that the flanges may extend past the edge 1510E. Still, theflanges may be moveable or retractable such that when case units areloaded into the payload bed 1510 the flanges are moved to extend pastthe edge 1510E to guide the case units into the payload area and oncethe case units are loaded, the flanges are retracted so they do notprotrude past the edge 1510E. Also, the flanges may be pivotable betweena vertically upright position and the angled position shown in, forexample, FIG. 7B.

A fence 1510F may be located at a side opening 1510P of the payload bed1510. In the embodiments the fence 1510F may be attached to the frame110F in any suitable manner such as with fasteners or welding. It isnoted that the fence 1510F may form part of the frame 110F or be ofunitary construction with the frame 110F. In the embodiments the fencemay include slots 1510FS disposed between stopping members 1510FM. Theslots 1510FS may be configured to allow the fingers 1540 to extendthrough the fence 1510F between the stopping members 1510FM in asubstantially lowered position so that the fingers 1540 can be, forexample, extended into a storage shelf 600 below a case unit. Thestopping members 1510FM may be configured to extend above the payloadbed 1510 to form a barrier that substantially prevents case units fromexiting the payload bed 1510 once the case units are positioned on thepayload bed 1510. In this example, the number of slots 1510FS is equalto the number of fingers 1540 but in alternate embodiments, the fence1510F may be configured such that more than one finger 1540 passesthrough a single slot (e.g. the number of slots is less than the numberof fingers). It should be noted that the fence may also have anysuitable configuration for preventing case units from exiting thepayload area when the case units are carried by the bot 110. Forexample, the fence may be movable so that the stopping members areretractable such that when in an extended configuration the fenceprevents the case units from exiting the payload area.

The payload bed 1510 may include any suitable payload supports forsupporting the case units when the case units are carried by the bot110. For exemplary purposes only, in the embodiments the payloadsupports may include a “fluid” (or otherwise movable) bed. In oneexample, the bed may include rollers 1510R, where a rotational axis ofeach roller 1510R is disposed substantially transversely (or laterally)to the longitudinal axis 6000 of the bot 110. The payload supports mayalso be belts, ball bearings or any other suitable “fluid” support thatmoves the case units on the payload bed for at least in part justifyinga location of the case unit relative to the payload bed/bot as will bedescribed in greater detail below. Each roller may be supported withinthe frame 110F in any suitable manner. In this example, the rollers maybe rotatably supported on one end at least in part by the fence 1510Fadjacent the side opening 1510P of the payload bed 1510 and rotatablysupported on the other opposite end by any suitable frame member, suchas frame member 110M (FIG. 9). In the embodiments the rollers 1510R (orother suitable payload supports) may be inter-disposed with fingers 1540of the bot 110 in an alternating manner. It is noted that the rollers1510R and the fingers 1540 may be arranged relative to each other in anysuitable manner. The rollers may be connected to any suitable drive 1532(FIG. 8) for rotating the rollers 1510R about their axes for moving caseunits on the payload bed 1510 as will be described in greater detailbelow. For exemplary purposes only, the drive 1532 may be a belt andpulley drive 1533 as shown in FIG. 8 but it should be understood thatthe drive 1532 may be any drive capable of causing rotation of therollers 1510R.

The fingers 1540 of the bot 110 extend laterally relative to thelongitudinal axis 6000 of the bot. The fingers 1540 are also capable ofmovement in the direction of arrow 1673 (e.g. in a directionsubstantially perpendicular to the direction 1550 of extension andretraction of the fingers). The fingers may be driven by any suitabledrive for lifting the pickfaces 1700P over the fence 1510F and into/outof the payload bed 1510 of the bot 110. One example, of a drive unitthat may drive the fingers 1540 can be found in U.S. Provisional PatentApplication No. 61/423,388 entitled “AUTOMATED BOT TRANSFER ARM DRIVESYSTEM,” and filed on Dec. 15, 2010 (now U.S. patent application Ser.No. 13/326,993 filed on Dec. 15, 2011), previously incorporated byreference.

A case unit contact member 1530 may be movably located at leastpartially within the payload area. The case unit contact member 1530 maybe driven laterally in the direction of arrow 1550 by any suitable drive1531. For exemplary purposes only, the drive 1531 may be a belt andpulley drive 1534 (FIG. 9) but it should be understood that the drivemay be any suitable drive for causing movement of the case unit contactmember in the direction of arrow 1550. In the embodiments both of thecase unit contact member 1530 and the fingers 1540 are configured tomove laterally in the direction of arrow 1550. The case unit contactmember 1530 may be configured to move along rails 1530R1, 1530R2. Therails may be mounted to the frame 110F in any suitable manner forguiding the movement of at least the case unit contact member 1530. Itshould be understood that the movement of the case unit contact member1530 may be guided in any suitable manner. For exemplary purposes only,referring to FIG. 9, the case unit contact member 1530 may have slidemembers 1530D1, 1530D2 for movably coupling the case unit contact member1530 to the rails 1530R1, 1530R2. The case unit contact member 1530 maybe independently movable in the direction of arrow 1550 for engagingcase units disposed on the payload bed 1510 as will be described ingreater detail below.

Referring to FIGS. 6 and 10 the case unit contact member 1530 may beconfigured to allow the fingers to move in the direction of arrow 1673(e.g. perpendicular to the plane of extension and retraction of the casecontact member 1530 and fingers 1540 in the direction of arrow 1550).For example, the case unit contact member 1530 may include any suitableslots 1680 that allow each finger to be lifted in the direction of arrow1673 without substantially contacting the case unit contact member 1530.In this example, the case unit contact member has a slot 1680 for eachfinger 1540 but it should be understood that the slots 1680 may have anysuitable configuration such as for example, a configuration thatallocated one slot to more than one finger 1540. As described above, thefence 1510F includes slots 1510FS that allow the fingers 1540 to passthrough the fence 1510 in a substantially lowered position as well as ina raised position when transferring case units to and from the payloadbed 1510.

In other aspects, referring to FIG. 7C, the bot 110 may include one ormore side blades 1535G mounted to the bot arm 110A. One or more of theblades 1535G may be moved along the longitudinal axis 6000 of the bot110 in the direction of arrow 1550X for aligning the pickface (e.g. oneor more case units 1700A) on the bot arm 110A. The translationalmovement of the one or more side blades 1535G may allow for thepositioning of the bot payload anywhere along the longitudinal axis ofthe bot within the bot payload area and may provide fine adjustment forcase positioning onto the storage shelves 600. It is noted that in thisaspect the side blades 1535G may not carry, transport or lift the caseunits 1700A but may aid in case unit 1700A control during picking andplacing the case units. It is noted that one side blade 1535G may befixed and act as a datum for aligning the case units 1700A.

Referring again to FIGS. 1, 6, 7A and 7B the bot 110 may also includeany suitable sensor(s) 1703 for detecting the pickface 1700P (and caseunits 1700 that make up the pickface) as they are transferred to andfrom the payload bed 1510. In the embodiments the sensor 1703 may be athrough-beam sensor. The sensor 1703 may include a transmitter 1701 andreceiver 1702 that are, for example, mounted to the frame (in anysuitable manner) adjacent a side opening 1510P of the payload bed 1510.The sensor 1703 may be configured and positioned on the bot 110 to sensethe edges of the pickface 1700P when the pickface 1700P is transferredbetween, for example, a storage shelf 600 or multilevel verticalconveyors 150A, 150B and the payload bed 1510. In the embodiments thesensor 1703 may be configured to sense the leading and trailing edges1700A, 1700B of the pickface 1700P as the pickface 1700P passes by thesensor 1703 to determine, for example, the depth D of the pickface1700P. It should be understood that the sensor may be configured tosense any suitable feature of the pickface 1700P (e.g. the pickface as aunit and/or each individual case unit of the pickface) for determining,for example, any suitable dimensions of the pickface 1700P. In theembodiments, the bot controller 1220 (or any other suitable controllersuch as for example the control server 120) may be configured toregister a detection signal(s) from the sensor 1703 during transfer ofthe case unit(s) to and/or from the bot 110. The controller 1220 may beconfigured to respond to the detection of the leading edge 1700A andtrailing edge 1700B of the pickface 1700P for determining the depth D ofthe pickface 1700P. As may be realized, which edge of the pickface isthe leading edge depends on which direction the pickface 1700P istravelling. For example, as the pickface 1700P enters the payload areathe edge closest to the case unit contact member 1530 is the leadingedge and as the pickface 1700P leaves the payload area the edge closestto the case unit contact member 1530 is the trailing edge of thepickface 1700P. For exemplary purposes only, the controller 1220 may beconfigured to use the leading and trailing edge sensor signals alongwith any other suitable information/data (such as for example indexingof a drive that drives the movement of fingers 1540 as they are extendedand retracted from/to the payload bed area) for determining the pickfacedepth D.

The sensor 1703 may also be configured to sense if the pickface 1700Pextends beyond the opening 1510P of the payload bed 1510. If thepickface does extend beyond the opening of the payload bed 1510 thecontroller 1220 may be configured to cause the bot 110 to time out (e.g.halt operation) so that corrective action can be taken if such an“overhanging” of the payload is detected. Such corrective action mayinclude but is not limited to returning the payload to the storage shelf600 from which the case was picked or if the case was picked from amultilevel vertical conveyor to a storage shelf in a location where thecase units/pickfaces can be inspected and redirected to an appropriatelocation within the storage and retrieval system. Such corrective actionmay also include the bot effecting the stopping of the multilevelvertical conveyor either through communication between the bot and themultilevel vertical conveyor or through communication with, for example,the control server 120 (or any other suitable controller thatcommunicates with both the bots and the multilevel vertical conveyor).As may be realized, the bot may include other suitable sensors todetermine what amount the pickface 1700P extends beyond the opening1510P of the payload bed 1510 where the controller 1220 only allows thebot 110 to be redirected to, for example, an inspection area if theoverhang of the pickface is less than a predetermined overhang amount.The predetermined overhang amount may be any suitable overhang distancesuch that the overhanging pickface will not contact the structure of thestorage and retrieval system, other bots or other pickfaces duringredirection to, for example, the inspection area. As may also berealized, the sensor 1703 can also be used to detect and measure anygaps between the cases of the pickface.

In the embodiments, the bot 110 may also have any suitable sensors fordetecting the length L (FIG. 7) of the pickface 1700P. For example, thebot 110 may include sensors 1713A, 1713B each disposed at oppositelongitudinal ends of the payload bed 1510. For exemplary purposes only,the sensors 1713 may be contact plates, through beam sensors, load cellsor any other suitable sensors that detect, for example, substantialcontact between the case unit and the side of the payload bed 1510. Thebot controller 1220 may also be configured to monitor strain (e.g. anincrease in current, etc.) on the drive 1532 for detecting substantialcontact between the case unit 1700 and the side 151S1, 151S2. It shouldbe understood that while the sensors 1713 are shown in the figures asbeing located adjacent the sides 1510S1, 1510S2, the sensors 1713 may belocated in any suitable location of the bot 110 for sensing thesubstantial contact between the case unit and the sides 1510S1, 1510S2.

In the embodiments, when the pickface 1700P is disposed on, for example,the rollers 1510R of the payload bed 1510, the rollers may be driven ina first direction 1551 until the pickface 1700P is sensed by a first oneof the sensors 1713A, 1713B (e.g. the pickface substantially contacts aside 1510S1, 1510S2 of the payload bed 1510). A first detection signalmay be sent to, for example, the bot controller 1220 indicating thepickface is disposed at a first side of the payload bed 1510. Where thepickface includes more than one case unit the rollers may continue to bedriven a predetermined amount of time after a first case unit of thepickface 1700P is sensed by the sensor 1713A, 1713B so that theremaining case units 1700 of the pickface 1700P also substantiallycontact the side 1510S1, 1510S2 of the payload bed 1510. The rollers maythen be driven in the opposite direction 1551 so that the pickface isdriven towards and is sensed by the other sensor 1713A, 1713B (e.g.substantially contacts the other side 1510S1, 1510S2) disposed on theopposite side of the payload bed 1510. A second detection signal may besent to, for example, the bot controller 1220 indicating the pickface isdisposed at a second side of the payload bed 1510. Again where thepickface 1700P includes more than one case unit the roller may continueto be driven a predetermined amount of time after a first one of thecase units is sensed by the sensor 1713A, 1713B to allow the other caseunits of the pickface to substantially contact the side 1510Sa, 1510S2.The bot controller 1220 may be configured to determine the length L ofthe pickface using the first and second detection signals from thesensors 1713A, 1713B in combination with, for example, data regardingthe operation of the bed drive or motor 1532. It should be understoodthat the length L of the pickface 1700P may be determined in anysuitable manner using any suitable sensors by any suitable processor orcontroller. In one example, the bot 110 may be configured to sendpickface measurement data to, for example, control server 120 fordetermining the measurements of the pickface.

Referring to FIGS. 1, 5, 6, 7A, 7B, 8, 10 and 11 an exemplary operationof the bot 110 will be described. The bot 110 may be instructed by, forexample the control server 120 to pick a pickface 1700P from amultilevel vertical conveyor 150A or a storage shelf 600. The bot 110extends the fingers 1540 through the slots 1510FS in the fence 1510F andunderneath the case unit to be picked. The pickface is lifted by thefingers 1540 and carried into the payload bed area. As may be realizedthe fingers 1540 may be raised so that when the case unit(s) aretransferred into and out of the payload area of the frame 110F, the caseunit(s) are carried over the stopping members 1510FM of the fencesubstantially without contacting the stopping members 1510FM. As thefingers are retracted into the payload bed area the controller 1220determines the depth D of the pickface 1700P as described above (FIG.11, Block 1102). For example, as the pickface 1700P is carried into thepayload area of the bot 110 the sensor 1703 senses a first or leadingedge 1700A as well as the second or trailing edge 1700B of the pickface1700P as well as any gaps between, for example, the cases that form thepickface where the pickface includes multiple cases. As described above,the controller 1220 detects the signals from the sensor 1703corresponding to the sensing of the first and second edges 1700A, 1700Band along with other suitable information (such as for example, dataregarding the operation of the finger extension/retraction drive motor)determines the depth D of the pickface 1700P being transferred into thepayload area.

The bot controller 1220 and/or the control server 120 may be programmedwith an expected depth of the pickface 1700P being picked by the bot. Inthe embodiments the bot controller 1220 may communicate with the controlserver 120 and inform the control server of the pickface depth D. If thedetermined pickface depth D matches the expected pickface depth then aconfirmation may be sent by the control server 120 to the bot controller1220 that the correct pickface 1700P has been picked and commands thebot 110 to proceed with transportation of the pickface 1700P. In theembodiments, if the determined pickface depth D does not match theexpected pickface depth then the control server 120 commands the bot 110to return the pickface 1700P to the storage shelf 600 from which thepickface 1700P was obtained or commands the bot 110 to redirect thepickface 1700P to an area of the storage and retrieval system where thepickface 1700P can be, for example, inspected. In the embodiments if thedetermined pickface depth D does not match the expected pickface depththe bot 110 may be configured to verify its location within the storageand retrieval system 100 and/or re-measure the depth D of the case unit.If the pickface depth D is determined to be incorrect after bot locationverification and/or pickface depth re-measurement a fault signal may besent to, for example, the control server 120 and the bot may return thepickface 1700P back to the storage shelf 600 from which the pickface1700P was obtained or redirect the pickface 1700P to any other suitablelocation within the storage and retrieval system. The bot 110 may thenproceed to, for example, another storage location, multilevel verticalconveyor, etc. for picking another case unit.

If the pickface 1700P is verified as being the correct case unit, thebot 110 may be configured to justify the pickface 1700P to apredetermined position on the payload bed 1510 when the case unit istransferred into the payload area of the frame 110F (FIG. 11, Block1103). For example, after the fingers are retracted and the case unit ispositioned over the payload bed 1510 the fingers 1540 may be lowered sothat the pickface 1700P is supported by, for example, the rollers 1510R(or any other suitable supports) of the payload bed 1510. The bot 110may drive the rollers 1510R, as described above for determining thelength L of the pickface, such that the pickface 1700P is located insubstantial contact with a side 1510S1, 1510S2 of the payload bed 1510.When the pickface 1700P is in substantial contact with a side 1510S1,1510S2, the bot controller 1220 may detect a signal from one of thesensors 1713A, 1713B and instruct the drive 1532 to stop driving therollers 1510R after a predetermined time period as described above sothat all case units 1700 of the pickface are in substantial contact withthe side 1510S1, 1510S2. As may be realized movement of the pickface inthe direction of arrow 1551 (e.g. in the direction of the longitudinalaxis 6000 of the bot 110) registers a position of or locates pickface1700P relative to the bot 110 along one axis (e.g. the longitudinal axisof the bot).

The bot 110 may also be configured to register the pickface 1700P alonga second axis (e.g. the lateral axis of the bot) so that the lateral andlongitudinal position of the pickface 1700P relative to the bot 110 isknown. For example, a second datum reference may be formed by, forexample, the fence 1510F. It is noted that the second reference datum,as well as the first reference datum, may be formed by any suitablefeatures of the payload bed 1510. In the embodiments, the case unitcontact member 1530 may be operated through any suitable drive, such asdrive 1531, to move the case unit contact member 1530 towards the sideopening 1510P of the payload bed 1510 for contacting and pushing thepickface 1700P substantially against the fence 1510F for locating thepickface 1700P laterally relative to the bot 110. The bot may have anysuitable sensors 1714, which may be substantially similar to sensors1713, for detecting the substantial contact between the pickface and thefence 1510F. It is noted that the bot controller 1220 may be configuredto monitor strain (e.g. an increase in current, etc.) on the drive 1531for detecting substantial contact between the pickface 1700P and thefence 1510F. As may be realized the sensors 1714 may be positioned atany suitable location relative to the payload bed 1510 for detecting thesubstantial contact between the pickface 1700P and the fence 1510F. Asmay also be realized, both drives 1531, 1532 may operate substantiallysimultaneously or independently of each other for moving the pickface inthe directions of arrows 1550, 1551 for substantially contacting thefirst and second references datums (e.g. one of the sides 1510S1, 1510S2and the fence 1510F). In this manner, as the pickface is in substantialcontact with first and second reference datums (which may besubstantially perpendicular to each other) the pickface 1700P isrepeatably positioned at a predetermined location on the payload bed1510.

The case unit contact member 1530 may remain in substantial contact withthe pickface 1700P and work in conjunction with the fence 1510F (asshown in e.g. FIG. 10) for actively gripping the pickface 1700P betweenthe case unit contact member 1530 and fence 1510F during transport ofthe pickface on the bot 110 (FIG. 11, Block 1104). To grip the pickface1700P the bot 110 may move the case unit contact member a distancedependent on the depth D of the pickface 1700P so that the case unitcontact member effects gripping of the pickface between the case unitcontact member and the fence. In this manner gripping the pickface 1700Pallows the position of the pickface 1700P relative to the bot 110 to besubstantially maintained during transport of the pickface 1700P as wellas prevent the pickface from escaping or falling off of the payload bed1510 during transport. It is noted that the pickface may be activelygripped by the bot 110 during transport of the pickface in any suitablemanner.

The bot 110 may be instructed by the control server 120 to transport thepickface 1700P located on the payload bed 1510 to a predeterminedlocation (e.g. destination) within the storage and retrieval system 100.At the predetermined destination the case unit contact member 1530 maybe moved to release the grip on the pickface 1700P. In the embodimentsthe bot controller 1220 may cause the drive 1532 to move the rollers1510R so that the pickface 1700P is moved in the direction of arrow 1551a predetermined distance away from the first reference datum (e.g. oneof sides 1510S1, 1510S2) so the pickface 1700P can be lifted off of thepayload bed 1510 and transferred off of the bot without substantialcontact with the sides of the payload bed 1510 (e.g. unimpaired travelof the pickface 1700P from the payload bed). The bot controller 1220 maybe configured to receive signals from, for example, sensors 1713 orobtain any other suitable information (such as from encoders on thedrive 1532) for determining a distance between the pickface 1700P andthe side 1510S1, 1510S2. When the determined distance is substantiallyequal to, for example, a predetermined distance (e.g. stored in a memoryof the bot or control server 120) the bot controller 1220 may cause thedrive 1532 to stop movement of the pickface 1700P. The bot 110 may alsocause the case unit contact member to push the pickface 1700P againstthe fence 1510F after the pickface 1700P is moved away from the side1510S1, 1510S2 so that the pickface 1700P is re-justified against thefence and all case units in the pickface are in substantial contact withone another. The re-justification and compacting (e.g. moving the caseunits together) of the pickface may be monitored in any suitable mannersuch as with any suitable sensors (such as those described above) and/ormonitoring a condition of one or more of the bot drive motors such asthe motors 1531, 1532. As the distance between the pickface 1700P andside 1510S1, 1510S2 is tracked by the controller 1220 and the pickface1700P is re-justified against the fence 1510F the relative positionbetween the pickface 1700P and the bot may be maintained as having aknown relationship allowing the bot to place the pickface 1700P on, forexample, a storage shelf 600 in a predetermined location. Thepredetermined location of the pickface and each of the case unitstherein may be stored in any suitable location such as, for example, ina memory of control server 120 for use when picking pickfaces from theirrespective locations on the storage shelves.

The bot controller 1220 causes the fingers 1540 to lift the pickface1700P off of the rollers 1510R and above the stopping members 1510FM ofthe fence 1510F and extend laterally away from the bot 110 for placingthe pickface 1700P at a desired location. When the pickface 1700P islocated above its destination location, on for example, the storageshelf 600, the fingers 1540 are lowered between the stopping members1510FM of the fence (e.g. into the slots 1510FS) and the pickface 1700Pis transferred onto, for example, the support surface 620H1, 620H2 ofthe slatted storage shelf 600 for placing the pickface 1700P on theshelf 600 (FIG. 11, Block 1105).

In a first aspect of the disclosed embodiments, an autonomous transportrobot for transporting a payload is provided. The autonomous transportrobot includes a payload bed having at least one reference datum surfaceand at least one payload justification device, the at least one payloadjustification device being configured to position a payload on thepayload bed in substantial contact with the at least one reference datumsurface to place the payload in a predetermined position on the payloadbed.

In accordance with the first aspect of the disclosed embodiments, the atleast one reference datum surface includes a first and second referencedatum surfaces disposed substantially perpendicular to one another andone of the first and second reference datum surfaces is substantiallyparallel with a longitudinal axis of the autonomous transport robot.

In accordance with the first aspect of the disclosed embodiments, the atleast one justification device includes a first justification deviceconfigured to move the payload in a first direction to substantiallycontact the first reference datum surface and a second justificationdevice configured to move the payload in a second direction,substantially perpendicular to the first direction, to contact thesecond reference datum surface.

In accordance with the first aspect of the disclosed embodiments, thefirst justification device includes driven rollers that form a payloadsupport surface of the payload bed.

In accordance with the first aspect of the disclosed embodiments, thesecond justification device includes a driven pusher bar.

In accordance with the first aspect of the disclosed embodiments, theautonomous transport robot includes at least one sensor for detectingthe substantial contact between the payload and at least one of thefirst and second reference datum surfaces.

In accordance with the first aspect of the disclosed embodiments, thefirst justification device is configured to move the payload apredetermined distance away from a respective one of the reference datumsurfaces when the payload is transferred off of the payload bed and thesecond justification device is configured to re-justify the payloadagainst the second reference datum surface.

In accordance with the first aspect of the disclosed embodiments, theautonomous transport robot includes a retaining fence disposed at anopening of the payload bed, the autonomous transport robot furtherincluding a driven pusher bar movably disposed at least party above thepayload bed, the retaining fence and the driven pusher bar beingconfigured to actively grip the payload during transport of the payloadon the autonomous transport robot.

In accordance with the first aspect of the disclosed embodiments, theautonomous transport robot further comprises at least one sensor fordetecting at least one dimension of the payload.

In accordance with a first sub-aspect of the first aspect of thedisclosed embodiments, the autonomous transport robot further includes aretractable effector for transferring the payload between a payloadholding area and the payload bed, the payload bed including guidesurfaces configured to guide the payload into an area of the payload bedduring transfer of the payload onto the autonomous transport robot.

In accordance with the first sub-aspect of the first aspect of thedisclosed embodiments, the effector is configured to be raised frombelow the payload bed to a position at least partially above a retainingfence disposed at an opening of the payload bed, the retaining fenceextending above the payload bed and being configured to at least in partretain the payload on the payload bed.

In accordance with a second aspect of the disclosed embodiments, anautonomous transport robot for transporting a payload within a storageand retrieval system is provided. The autonomous transport robotincludes a payload bed having an opening, an effector for transferringthe payload to and from the payload bed at least party through theopening, at least one sensor disposed adjacent the opening for sensing afirst and second edge of the payload and a controller configured todetermine a dimension of the payload based at least in part on thesensing of the first and second edge of the payload and to compare thedetermined dimension of the payload with a predetermined dimension ofthe payload.

In accordance with a first sub-aspect of the second aspect of thedisclosed embodiments, the controller is configured generate a faultsignal if the detected dimension and the predetermined dimension do notsubstantially match.

In accordance with the first sub-aspect of the second aspect of thedisclosed embodiments, the controller is further configured to cause theeffector to return the payload to a payload holding area from which itcame if the detected dimension and the predetermined dimension do notsubstantially match.

In accordance with the first sub-aspect of the second aspect of thedisclosed embodiments, the controller is further configured to verify aposition of the autonomous transport robot within the storage andretrieval system if the detected dimension and the predetermineddimension do not substantially match.

In accordance with a second sub-aspect of the second aspect of thedisclosed embodiments, the at least one sensor comprises at least onesensor for detecting other edges of the payload substantially transverseto the first and second edges and the controller is configured todetermine another dimension of the payload that is substantiallytransverse to the dimension based at least in part on the detection ofthe other edges.

In accordance with the second sub-aspect of the second aspect of thedisclosed embodiments, the autonomous transport robot further comprisesa payload justification device for moving the payload in a direction onthe payload bed substantially transverse to a direction of loading ofthe payload onto the payload bed, the payload justification device beingconfigured to at least in part facilitate the detection of the anotherdimension.

It should be understood that the exemplary embodiments disclosed hereincan be used individually or in any suitable combination thereof. Itshould also be understood that the foregoing description is onlyillustrative of the embodiments. Various alternatives and modificationscan be devised by those skilled in the art without departing from theembodiments. Accordingly, the present embodiments are intended toembrace all such alternatives, modifications and variances that fallwithin the scope of the appended claims.

What is claimed is:
 1. A method for transporting a payload, the methodcomprising: providing an autonomous transport robot having a payloadbed, the payload bed having at least one reference datum surface withrespect to a payload storage location; providing the autonomoustransport robot with at least one payload justification device; andpositioning, with the at least one payload justification device, apayload on the payload bed in substantial contact with the at least onereference datum surface that is arranged relative the payload bed toplace each payload so that a payload side is at a repeatablepredetermined longitudinal position, independent of a payload size, onthe payload bed relative to at least a longitudinal axis of theautonomous transport robot.
 2. The method of claim 1, wherein the atleast one reference datum surface includes a first and second referencedatum surfaces disposed substantially perpendicular to one another andone of the first and second reference datum surfaces is substantiallyparallel with the longitudinal axis of the autonomous transport robot.3. The method of claim 2, wherein the at least one justification deviceincludes a first justification device and a second justification device,the method further comprising moving, with the first justificationdevice, the payload in a first direction to substantially contact thefirst reference datum surface, and moving, with the second justificationdevice, the payload in a second direction, substantially perpendicularto the first direction, to contact the second reference datum surface.4. The method of claim 3, wherein the first justification deviceincludes driven rollers that form a payload support surface of thepayload bed.
 5. The method of claim 3, wherein the second justificationdevice includes a driven pusher bar.
 6. The method of claim 2, furthercomprising detecting, with at least sensor of the autonomous transportrobot, the substantial contact between the payload and at least one ofthe first and second reference datum surfaces.
 7. The method of claim 1,wherein the autonomous transport robot includes a retaining fencedisposed at an opening of the payload bed and a driven pusher barmovably disposed at least partly above the payload bed, the methodfurther comprising actively gripping, with the retaining fence and thedriven pusher bar, the payload during transport of the payload on theautonomous transport robot.
 8. The method of claim 1, further comprisingdetecting, with at least one sensor of the autonomous transport robot,at least one dimension of the payload.
 9. The method of claim 1, furthercomprising transferring the payload between a payload holding area andthe payload bed with a retractable effector of the autonomous transportrobot, and guiding, with guide surfaces of the payload bed, the payloadinto an area of the payload bed during transfer of the payload onto theautonomous transport robot.
 10. The method of claim 9, furthercomprising raising the retractable effector from below the payload bedto a position at least partially above a retaining fence disposed at anopening of the payload bed, and retaining at least in part, with theretaining fence extending above the payload bed, the payload on thepayload bed.
 11. A method for transporting a payload, the methodcomprising: providing an autonomous transport robot having a payloadbed, the payload bed having at least one reference datum surface withrespect to a payload storage location; providing the autonomoustransport robot with at least one payload justification device; andpositioning, with the at least one payload justification device, apayload on the payload bed in substantial contact with the at least onereference datum surface that is arranged relative the payload bed toplace each payload so that a payload side is at a repeatablepredetermined longitudinal position, independent of a payload size, onthe payload bed relative to at least a longitudinal axis of theautonomous transport robot; wherein the at least one reference datumsurface includes a first and second reference datum surfaces disposedsubstantially perpendicular to one another and one of the first andsecond reference datum surfaces is substantially parallel with thelongitudinal axis of the autonomous transport robot, and wherein thepayload bed effects, raising the payload from the payload bed andplacing the payload on a support rack in a rack position with respect toa first rack direction determined by the repeatable predeterminedlongitudinal position on the payload bed set by the first referencedatum and with respect to a second rack direction determined by thesecond reference datum so that the payload is placed in the rackposition as determined by the second reference datum.
 12. The method ofclaim 11, wherein the autonomous transport robot includes a retainingfence disposed at an opening of the payload bed and a driven pusher barmovably disposed at least partly above the payload bed, the methodfurther comprising actively gripping, with the retaining fence and thedriven pusher bar, the payload during transport of the payload on theautonomous transport robot.
 13. The method of claim 11, furthercomprising detecting, with at least one sensor of the autonomoustransport robot, at least one dimension of the payload.
 14. The methodof claim 11, further comprising transferring the payload between apayload holding area and the payload bed with a retractable effector ofthe autonomous transport robot, and guiding, with guide surfaces of thepayload bed, the payload into an area of the payload bed during transferof the payload onto the autonomous transport robot.
 15. The method ofclaim 14, further comprising raising the retractable effector from belowthe payload bed to a position at least partially above a retaining fencedisposed at an opening of the payload bed, and retaining at least inpart, with the retaining fence extending above the payload bed, thepayload on the payload bed.
 16. The method of claim 11, wherein the atleast one justification device includes a first justification device anda second justification device, the method further comprising moving,with the first justification device, the payload in a first direction tosubstantially contact the first reference datum surface, and moving,with the second justification device, the payload in a second direction,substantially perpendicular to the first direction, to contact thesecond reference datum surface.
 17. The method of claim 16, wherein thefirst justification device includes driven rollers that form a payloadsupport surface of the payload bed.
 18. The method of claim 16, whereinthe second justification device includes a driven pusher bar.
 19. Themethod of claim 11, further comprising detecting, with at least sensorof the autonomous transport robot, the substantial contact between thepayload and at least one of the first and second reference datumsurfaces.